TypeScript alias alternative to Static Factory Method: avoid static create and restore methods on DDD, just simplify

Email.ts

export class Email {
  constructor(private _value: string) {
    if (!this.isValid()) {
      throw new Error("Invalid email");
    }
  }

  private isValid(): boolean {
    /**
     * Must have a valid username and domain.
     * Allows letters, digits, hyphens, and underscores in the username.
     * Allows letters and hyphens in the domain.
     * Must have a valid top-level domain (TLD).
     * Forbids the use of alias with '+' in the username.
     */
    const regex = /^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}$/;
    return regex.test(this._value);
  }
  
  get value(): string {
    return this._value.trim();
  }
}

index.d.ts

declare global {
  type ExcludeMethods<T> = Pick<
    T,
    {
      [K in keyof T]: T[K] extends Function ? never : K;
    }[keyof T]
  >;
  type IfEquals<X, Y, A = X, B = never> = (<T>() => T extends X
    ? 1
    : 2) extends <T>() => T extends Y ? 1 : 2
    ? A
    : B;
  type WritableKeys<T> = {
    [P in keyof T]-?: IfEquals<
      { [Q in P]: T[P] },
      { -readonly [Q in P]: T[P] },
      P
    >;
  }[keyof T];
  type ExtractClassProps<T> = ExcludeMethods<Pick<T, WritableKeys<T>>>;
  // type ClassProps<T, U = ExtractClassProps<T>> = Omit<
  //   ExtractClassProps<T>,
  //   keyof U
  // > &
  //   U;
  type ClassProps<
    T,
    U = ExtractClassProps<T>,
    V extends keyof T = never
  > = Omit<ExtractClassProps<T>, keyof U | V> & U;
}

export {};

main.ts

import { User } from "./User";

const main = async () => {
  const newUser = new User({ // naturally replaces the static create method
    email: "[email protected]",
    password: "123456789",
    surname: "Doe",
    givenName: "John",
    middleName: "Smith",
  });
  console.log(newUser.id); // get the new generated uuid
  await newUser.password.hash(); // hash the password
  console.log(newUser.password.value); // get the hashed password as string
  console.log(newUser.fullName); // `John Smith Doe`

  const oldUser = new User({ // naturally replaces the static restore method
    id: "bf54c5a8-3ec4-4c5c-9577-4ec638dbf00f",
    email: "[email protected]",
    password: "$argon2...", // hashed password
    surname: "Doe",
    givenName: "Jane",
  });
  const oldUserPassword = "123456789";
  console.log(oldUser.id); // get the old uuid `bf54c5a8-3ec4-4c5c-9577-4ec638dbf00f`
  console.log(oldUser.email.value); // get the email as string from Email value object `[email protected]`
  console.log(await oldUser.password.verify(oldUserPassword)); // verify the password (returns a boolean promise)
};

main();

Password.ts

import argon2 from "argon2";

export class Password {
  constructor(private _value: string) {
    if (argon2.needsRehash(this._value) && !this.isValid()) {
      throw new Error("Invalid password");
    }
  }

  private isValid(): boolean {
    /**
     * At least 8 characters.
     * At least one lowercase letter.
     * At least one uppercase letter.
     * At least one number.
     * At least one special character.
     */
    const regex =
      /^(?=.*[a-z])(?=.*[A-Z])(?=.*\d)(?=.*[@$!%*?&])[A-Za-z\d@$!%*?&]{8,}$/;
    return regex.test(this._value);
  }

  async hash(): Promise<void> {
    if (!argon2.needsRehash(this._value)) return;
    this._value = await argon2.hash(this._value);
  }

  async verify(password: string): Promise<boolean> {
    return await argon2.verify(this._value, password);
  }
  
  get value(): string {
    return this._value;
  }
}

User.ts

import crypto from "node:crypto";
import { Email } from "./Email";
import { Password } from "./Password";

export type UserProps = ClassProps<
  User,
  { // this second type is optional and will replace the original User class props
    email: string;
    password: string;
  }
>;

/**
 * UserProps will be:
 * {
 *   id?: string;
 *   email: string;
 *   password: string;
 *   surname: string;
 *   givenName: string;
 *   middleName?: string;
 * }
 */

export class User { // entity
  id?: string = crypto.randomUUID();
  email: Email;
  password: Password;
  surname: string;
  givenName: string;
  middleName?: string;

  constructor(props: UserProps) { // props allows you to use a single object instead of stacking multiple arguments in the constructor
    Object.assign(this, props);
    this.email = new Email(props.email); // value object
    this.password = new Password(props.password); // value object
  }

  get fullName(): string {
    return `${this.givenName} ${this.middleName ? `${this.middleName} ` : ""}${this.surname}`;
  }
  
  // more behavior...
}